Skip to content
History of Science Museum

Vertical Semicircle for Surveying, English, Early 19th Century?

Inventory Number 75677


Acknowledgement: © History of Science Museum, University of Oxford, inv.75677

Subject
Surveying
Item type
Object
Provenance
Not ascertained
Primary inscriptions
Unsigned and undated
Physical material
Copper Alloy
Dimensions
Diameter: 187mm
Inventory No
75677

Description

Inverted vertical semicircle with rack and pinion motion, perhaps from a Lean's miner's dial or a telescopic altazimuth theodolite. Rotating index has a thumb screw and the base and one support for the missing telescope. The semicircle has degrees on one side (with a silver Vernier) and scales for perpendicular feet and 'Underlie in a fathom' on the reverse.